The Preparation Of Three Porphyrin Coordination Polymers And Their Sensing Applications

Porphyrin is an organic heterocyclic aromatic compound with tetrapyrrole as the core,which exists widely in animals and plants,and plays a very important role in biological activities.Due to the special structure of porphyrins,it has rich chemical and photoelectric properties,the research and preparation of porphyrin-based compounds has attracted the interest of scientists because it has very important application value in chemical sensing,organic solar cells and photodynamic therapy.However,it is still a challenge that single emission is not suitable detection for complex samples.The preparation of novel porphyrin-based coordination polymers with dual emissions is highly desired.In this paper,porphyrin-based coordination polymers with dual emissions were designed and applied to chemical sensing.The specific work is as follows:1.Gadolinium─porphyrin（Gd─TCPP）complex was firstly synthesized,and nano porphyrin coordination polymer（NCPs@PEI）with dual emission properties was synthesized by using polyethyleneimine（PEI）as coating agent that change its surface state,resulting in increase the dispersion of the complex in water.In the process of p H increasing,the blue emission intensity decreases and the red emission intensity increases derived from protonation and deprotonation of pyrrolic nitrogen and amino groups in the NCPs@PEI by the change of p H value of the solution.The lg(I_{655 nm}I_{477 nm})exists a good linear relationship with p H.Based on the above characteristics,a ratiometric fluorescence sensor was developed to monitor the p H of solution.The sensor has good fluorescence reversibility proved by repeatable experiments.Moreover,by exploiting the electron transfer between Cu²⁺and nitrogen in porphyrin,the red emission of NCPs@PEI can be quenched by Cu²⁺,blue emission stays steady.which can be specifically detected Cu²⁺with a function of y=-0.0074x+0.5990 and the limit of detection is calculated to be 136 n M.The fluorescence sensing performance of NCPs@PEI on p H and Cu²⁺indicates that we have developed a good multi-target detection platform.2.Zr-TCPP-TBAPy was prepared by solvothermal method by connecting TCPP and TBAPy using zirconium ion as the central ion.When the material was ground and dissolved in water,acidic amino acids can reduce the solubility of the probe,leading to blue fluorescence quenching,which can be used for specific detection of glutathione that has a glycine unit.The standard function is y=0.0460x+0.0597 and the limit of detection is calculated to be 282 n M.However,the unground sample’s fluorescence can be enhanced by increased solubility in the alkaline environment provided by arginine,and have a good specific response to arginine with a function of y=0.0434x+0.2265,LOD=302 n M.Therefore,the distinguish ability between acid and basic amino acids was perfomed and demonstrated that this Zr-TCPP-TBAPy has great potential as an effective tool for amino acids researches.3.A dual-emission porphyrin-based fluorescent nanomaterial was preliminarily attempted to prepare.Porphyrins are metallized by the coordination of zinc and porphyrins passivated with surface active agent.In this work,a kind of carbon dots was prepared using ethylenediamine tetraacetic acid disodium as carbon source in a simple dry burning method.The surface of carbon dots contained abundant amino and hydroxyl groups.The modification of porphyrin was performed by the combination between carbon dots and porphyrin,in order to achieve the purpose of changing the performance of porphyrin.The preparation conditions were preliminarily explored.This method on dual-emission will provide a new route for multi-emission coordination polymers in the light of the tunable fluorescence of carbon dots.